The present invention relates to a double-sided floppy disk driving apparatus and, more particularly, to a floppy disk driving apparatus which has a mechanism for preventing two heads from coming into contact with each other when a recording medium is not loaded.
Conventional double-sided floppy disk driving apparatuses comprise a head load actuator for moving a pair of heads toward each other. Such a head load actuator is driven by a solenoid or the like. The heads are actuated and urged, using a predetermined pressure, against the two surfaces of a medium only when the medium is loaded correctly.
Recently, double-sided floppy disk driving apparatuses became available, in which the head load actuator is omitted. An apparatus of this type is mechanically interlinked with a mechanism for clamping the medium, so that its heads are moved toward each other.
An example of such a floppy disk driving apparatus will be now described with reference to FIGS. 1 to 3. The apparatus comprises a medium-clamping mechanism. The clamping mechanism has manually operated lever 1 to which cam 2 is connected. When lever 1 is pivoted, cam 2 is pivoted therewith, thereby pushing down swing arm 3. Arm 3 pushes down clamper pressure plate 4 and hence clamper 6. A medium is thus clamped between clamper 6 and a spindle (not shown). Clamper 6 is guided by clamper guide 5 so as to be vertically movable.
The apparatus also has a carriage mechanism. The carriage mechanism has carriage 7, which is guided in the radial direction of a medium by guide rail 8 and guide pin 11. Steel belt 9 is mounted on carriage 7. An intermediate portion of steel belt 9 is wound around pulley 10. Pulley 10 is mounted on the rotating shaft of stepping motor 14. When stepping motor 14 is activated, its rotation is converted into a linear movement by pulley 10 and steel belt 9, thereby reciprocating carriage 7 linearly. S0 head 13 for side 0 of the medium and S1 head 12 for side 1 of the medium are attached to carriage 7. S1 head 12 is biased downward by a spring (not shown), so as to move toward S0 head 13.
A paddle mechanism is provided on the side of the carriage and clamp mechanisms. The paddle mechanism comprises paddle plate 16, an end portion of which is mounted on a base plate, so as to be vertically pivotal. The base plate supports the mechanical portion of the floppy disk driving mechanism. Arm 16a and opener 17 are located on paddle plate 16. The distal end portion of arm 16a is located under the distal end portion of pressure plate 4 of the clamp mechanism. Opener 17 is located under head arm 15 provided on S1 head 12 of the carriage mechanism. Paddle plate 16 is biased to pivot upward by means a spring (not shown). When a medium is not clamped, opener 17 of paddle plate 16 pushes head arm 15 upward, and separates S1 head 12 from so head 13, as shown in FIG. 2. When clamper 6 is pushed down to clamp the medium, the distal end portion of pressure plate 4 pushes down arm 16a, thereby pivoting paddle plate 16 downward. Thus, opener 17 is moved downward in synchronism with downward pivot of paddle plate 16 and is separated from head arm 15. Head 12 is moved downward by the biasing force of the spring and clamps the medium together with head 13. Thus, heads 12 and 13 are abutted against the two sides of the medium, and read data out from or write data in the medium.
In the floppy disk driving apparatus having the above arrangement, assume that lever 1 is operated when no medium is loaded in the apparatus, and that the clamp mechanism is set in the clamping state. Then, as described above, since paddle plate 16 is pivoted downward to remove opener 17 from head arm 15, head 12 is moved downward by the biasing force of the spring and directly contacts head 13, as shown in FIG. 3. When the heads are brought into direct contact with each other, they are damaged. In addition, since the head surfaces are polished to a high smoothness, they provide a suction effect and the heads cannot be separated.
It is, therefore, an object of the present invention to provide a floppy disk driving apparatus wherein, when a medium is not loaded in the correct position, the heads are not brought into direct contact with each other, even if the clamp mechanism is set in a clamping state.
It is another object of the present invention to provide a floppy disk driving apparatus which has a mechanism for preventing direct contact between its heads, which has high operational reliability and a simple arrangement.